Hi, I'm experimenting with Drools and have troubles understanding the way accumulators work. Before i go and look at the source code i was wondering if the way the accumulators work is designed as described below or of it has something to do with my rules configuration. I'm using drools distibution 5.4.0. So this is my test case: I have 3 similar events and 1 rule containing an accumulator. So when firing the alerts obviously as the events are similar the same rule is fired. So accorrding to me when the rule is fired drools creates a new accumulator

and passed data for all events

but at the same time the first accumulator still exists

and receives only the datza for the second event. The 3rd event will trigger accumulate for context1 and context2 and then create a new accumulator with all the 3 events. This results in actually having 3 accumulators with exactly the same data.

I have created a dummy accumulator to test this: Here is the DRL rule "update profile" salience 1000 // Make sure this rule is always executed by giving it a very high salience no-loop true when $event: TestEvent() $profile: Profile( key == $event.key) $total : Number() from accumulate( TestEvent( $p : value, key == $event.key), test( $p ) ) then System.out.println("Total:" + $total); end Here is the output Event 1 Context created:137 Init called for context:137 accumulate called for context:137 object:80 Total called for context:137 Total:80 Event 2 Context created:858 Init called for context:858 accumulate called for context:858 object:80 Total called for context:858 accumulate called for context:137 object:41 accumulate called for context:858 object:41 Total called for context:858 Total called for context:137 Total:121 Total:121 Event 3 Context created:724 Init called for context:724 accumulate called for context:724 object:80 accumulate called for context:724 object:41 Total called for context:724 accumulate called for context:137 object:53 accumulate called for context:858 object:53 accumulate called for context:724 object:53 Total called for context:724 Total called for context:858 Total called for context:137 Total:174 Total:174 Total:174 How can i remove the accumulator after the rule is finished?

Regards, e -- View this message in context: http://drools.46999.n3.nabble.com/Accumulator-being-executed-depending-on... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Hi Wolfgang, thanks for the swift reply. Probalby you are right about the fact that a new context is created instead of a new accumulator. But why is it looping over all the context that are created for that accumulator?

Surely the output attached to the first thread is not what you would expect, is it?

I would like to just have 1 context, is that possbile?

Regards, e

Wolfgang, Again many thanks for you response but it's just not clear for me. According to me if i have 1 million TestEvents and after each insert I call fireAllRules i will end up with 1 million accumulate context of type test in my example. Meaning that if the event in my case belongs to the same customer the accumulate method will be called 1 million x 1 million. So that seems to me not really scalable. So i wonder as there is already a context created after the first accumulate and it seems to me that the engine is aware of it as for consecutive events it also calls the accumulate method on that context it should not create a new context. What is the purpose of a new context? The accumulate doesn't stop when i return a null contex, is there any other way to avoid creating that context? Regards, e Thx, e -- View this message in context: http://drools.46999.n3.nabble.com/Accumulator-being-executed-depending-on... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Hi Wolfgang, I couldn't agree more with your analysis unfortunately it seems that or i have something wrong with my rule or there is something wrong with the implementation? First off all the reserve was set to false this would mean that once the rule is finished the context shouldn't be available any more and therefore not updated when the rule is executed again (as recalculation would require all the facts to be processed again anyway). Now if my understanding is correct then this is not how drools behaves, you can see evidence of this in the trace of the first post. I tried returning true for the reverse but the behaviour is exactly the same. Each new fact creates a new context then for all matching facts the accuulate is called on that context. The accumulate method is called on all existing contexts for the new fact. Here is the rule (test just makes a sum of the values) import eu.mc2bis.drools.TestEvent; declare TestEvent @role(event) @timestamp( eventDate ) end rule "test accumulator" salience 100 // Make sure this rule is always executed by giving it a very high salience no-loop true when $event: TestEvent( $key:key) $total : Number( ) from accumulate( event : TestEvent( key == $key ) , test( 1 ) ) then System.out.println("-- Rule output Total for key:" + $key + " total:" + $total); end here is the output with reverse:false Main:inserting event with key:0 -> Accumulator: Context created:553 -> Accumulator: Init called for context:553 -> Accumulator: getResults() called for context:553 -> Accumulator: accumulate called for context:553 key:553 value:1 -> Accumulator: getResults() called for context:553 Main:fireAllRules start -- Rule output Total for key:0 total:1 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:454 -> Accumulator: Init called for context:454 -> Accumulator: accumulate called for context:454 key:454 value:1 -> Accumulator: getResults() called for context:454 -> Accumulator: accumulate called for context:553 key:553 value:1 -> Accumulator: accumulate called for context:454 key:454 value:1 -> Accumulator: getResults() called for context:454 -> Accumulator: getResults() called for context:553 Main:fireAllRules start -- Rule output Total for key:0 total:2 -- Rule output Total for key:0 total:2 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:695 -> Accumulator: Init called for context:695 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: getResults() called for context:695 -> Accumulator: accumulate called for context:553 key:553 value:1 -> Accumulator: accumulate called for context:454 key:454 value:1 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: getResults() called for context:695 -> Accumulator: getResults() called for context:454 -> Accumulator: getResults() called for context:553 Main:fireAllRules start -- Rule output Total for key:0 total:3 -- Rule output Total for key:0 total:3 -- Rule output Total for key:0 total:3 Main:fireAllRules finished Time (ms) required to update: 100k profiles = 30 Ended I would have expected: Main:inserting event with key:0 -> Accumulator: Context created:553 -> Accumulator: Init called for context:553 -> Accumulator: getResults() called for context:553 -> Accumulator: accumulate called for context:553 key:553 value:1 -> Accumulator: getResults() called for context:553 Main:fireAllRules start -- Rule output Total for key:0 total:1 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:454 -> Accumulator: Init called for context:454 -> Accumulator: accumulate called for context:454 key:454 value:1 -> Accumulator: getResults() called for context:454 -> Accumulator: accumulate called for context:454 key:454 value:1 -> Accumulator: getResults() called for context:454 Main:fireAllRules start -- Rule output Total for key:0 total:2 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:695 -> Accumulator: Init called for context:695 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: getResults() called for context:695 -> Accumulator: accumulate called for context:695 key:695 value:1 -> Accumulator: getResults() called for context:695 Main:fireAllRules start -- Rule output Total for key:0 total:3 Main:fireAllRules finished Time (ms) required to update: 100k profiles = 30 Ended Here is the output with reverse:true Main:inserting event with key:0 -> Accumulator: Context created:943 -> Accumulator: Init called for context:943 -> Accumulator: getResults() called for context:943 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:1 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:677 -> Accumulator: Init called for context:677 -> Accumulator: accumulate called for context:677 key:677 value:1 -> Accumulator: getResults() called for context:677 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: accumulate called for context:677 key:677 value:1 -> Accumulator: getResults() called for context:677 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:2 -- Rule output Total for key:0 total:2 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Context created:968 -> Accumulator: Init called for context:968 -> Accumulator: accumulate called for context:968 key:968 value:1 -> Accumulator: accumulate called for context:968 key:968 value:1 -> Accumulator: getResults() called for context:968 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: accumulate called for context:677 key:677 value:1 -> Accumulator: accumulate called for context:968 key:968 value:1 -> Accumulator: getResults() called for context:968 -> Accumulator: getResults() called for context:677 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:3 -- Rule output Total for key:0 total:3 -- Rule output Total for key:0 total:3 Main:fireAllRules finished Time (ms) required to update: 100k profiles = 32 Ended I would have expected: Main:inserting event with key:0 -> Accumulator: Context created:943 -> Accumulator: Init called for context:943 -> Accumulator: getResults() called for context:943 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:1 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Init called for context:943 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:2 Main:fireAllRules finished Main:inserting event with key:0 -> Accumulator: Init called for context:943 -> Accumulator: accumulate called for context:943 key:943 value:1 -> Accumulator: getResults() called for context:943 Main:fireAllRules start -- Rule output Total for key:0 total:3 Main:fireAllRules finished Time (ms) required to update: 100k profiles = 32 Ended Thank you for being so patient with me I'm sure I must be doing something wrong? Can you point me out to some documentation or sequence diagram how this is designed (if possible) or perhaps i just need to read the code ;-) Best Regards, e -- View this message in context: http://drools.46999.n3.nabble.com/Accumulator-being-executed-depending-on... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users